Invasion of the Clinging Jellyfish

The Shrewsbury and Manasquan Rivers were invaded this summer by a highly toxic, nocturnal species of the dime-sized Gonionemus vertens or clinging jellyfish – not seen there before.

So the state brought in Montclair State jellyfish experts to investigate. The New Jersey Department of Environmental Protection funded an emergency study with Montclair State to quantify and delineate the clinging jellyfish population.

Paul Bologna, biology professor and director of the University’s Marine Biology and Coastal Sciences program, and Biology Professor Jack Gaynor spearheaded the research effort by collecting specimens and analyzing their DNA.

Researcher Paul Bologna and students study jellyfish.

The team set up a clinging jellyfish habitat in their campus lab. “Given that this species has not been recorded in New Jersey, we need to understand its distribution and life history to establish a baseline and support the development of public education and management strategies,” explains Bologna.

While the adult jellyfish, or medusa, are a problem because of their venomous sting, it’s the resilient polyps, which attach to hard surfaces like bulkheads to reproduce, that pose a more lasting challenge. “It’s a vicious cycle – so you don’t really have a jellyfish problem, you have a polyp problem,” says Gaynor.

The team found a polyp on one of their jellyfish attracting devices in the Shrewsbury River. “This tells us that the adults have successfully reproduced in the river, which means that we are likely to see this species return again next spring or early next summer,” explains Gaynor.